There are a number of conventional methods and apparatuses for carrying an engine generally forward and below a wing of an airplane. Generally, in a conventional method and apparatus, a strut, attached to the engine, is connected to the wing, i.e., the wing box of an airplane, by means of various structural elements or interfaces which usually comprise one upper link, one diagonal brace, two side links and two midspar fittings or two upper spar fittings. Examples include U.S. Pat. No. 5,467,941, issued Nov. 21, 1995, to Chee, U.S. Pat. No. 5,181,675, issued Jan. 26, 1993, to Lardellier etal., U.S. Pat. No. 4,917,331, issued Apr. 17, 1990, to Hager etal., U.S. Pat. No. 4,560,122, issued Dec. 24, 1985, to Parkinson etal., U.S. Pat. No. 4,458,863, issued Jul. 10, 1984, to Smith, U.S. Pat. No. 4,437,627, issued Mar. 20, 1984, to Moorehead, and U.S. Pat. No. 4,079,981, issued Mar. 21, 1978, to Mahler et al.
However, in general, but more particularly in the case of new huge commercial transports now being contemplated, a number of new challenges must be met by airplane manufacturers. In particular, in some cases the wing-strut strength requirements may be at the maximum level the manufacturer would like to see. Thus, manufacturers have new primary objectives in designing strut-wing interface structures. For example, there is a desire to reduce strength requirements at the strut-wing interface. Also, it is highly desirable to improve the flutter/dynamic aspects in single-element configurations. As used herein, "single-element" means that the structure can withstand the total or partial failure of any one element of the engine/strut/wing attachment arrangement. In addition, aerodynamicists are insisting that aerostructural engineers reduce interface pin spacing, i.e., narrow the strut box width, to reduce drag and locate placement of the engine/nacelle/strut package (nacelle package) to minimize engine nacelle drag and optimize engine performance. The nacelle position is critical to performance of the airplane, and the nacelle package is typically placed as far forward of the wing as possible. As will be apparent to one of ordinary skill in the art, this last requirement imposes increased strength requirements on the strut-wing interface ordinarily resulting in heavier structures.